JPH11268422A - Heat-sensitive recording body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-sensitive body of which the image keeping quality and the heat-resistant base color stability are improved. SOLUTION: For this heat-sensitive recording body, 4,4'-bis(4- phenylsulfamoylphenylureide)diphenyl methane is used as a color-developer. In this case, the compound has a sufficient color-developability to make a dye precursor develop a color. Also, compared to a phynol based color-developer or the like which has been conventionally used, the heat-sensitive recording body shows an excellent performance in the image keeping quality of a recorded part and the heat-resistant base color stability of a white paper part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive recording medium having excellent image storability in a recording section.

[0002]

2. Description of the Related Art In general, a thermosensitive recording medium is prepared by grinding and dispersing a colorless or light-colored dye precursor as an electron donating compound and a developer as an electron accepting compound into fine particles. Mix, binder, filler, sensitizer,
A coating solution obtained by adding a lubricant and other auxiliaries is applied to a support such as paper, synthetic paper, film, plastic, etc., and develops color by an instantaneous chemical reaction caused by heating with a thermal head, hot stamp, laser light, etc. Get the record. These heat-sensitive recording materials are applied to a wide range of fields such as measuring recorders, computer terminal printers, facsimile machines, automatic ticket vending machines, and barcode labels.

However, with the recent diversification of recording devices for thermosensitive recording media and the development of higher performance, the quality required for thermosensitive recording media has become higher. In addition, with the spread of plain paper recording methods such as the electrophotographic method and the ink jet method, the thermal recording method has more opportunities to be compared with these plain paper recording methods. Therefore, for example, it is required that the stability of the recording portion (image) or the stability of the non-recording portion (ground color) of the thermal recording medium approach the same level as that of the plain paper recording method. In particular, from the viewpoint of storage stability of a recorded image, a heat-sensitive recording medium having excellent light resistance, oil resistance, water resistance, and plasticizer resistance has been required.

Particularly, in order to improve oil resistance and plasticizer resistance, an epoxy compound described in JP-A-4-97887, an aziridine compound described in JP-A-4-113888, and JP-A-63-163 in a thermosensitive coloring layer. Examples including various metal salts described in JP-A--22683 are known. However, the effect is insufficient.

Also, instead of the conventionally used phenolic color developer, a so-called non-phenolic color developer having an acidic atmosphere capable of coloring a dye precursor without a hydroxy group has been developed. I have. Until now, examples using urea, thiourea, phosphoric acid, phosphoric acid ester, amide, urethane, etc. as a non-phenolic color developer have been disclosed,
When these are used as a color developer, it is known that the image storability of the recording portion is improved as compared with a conventional phenol-based color developer.

For example, carbonyl sulfonamide compounds described in JP-A-4-282291, JP-A-6-99
No. 666, and the like. One of the causes of decolorization of the color image is the dissociation of the dye and the developer, but the non-phenolic developer is less soluble in water, oil, plasticizer, etc. than the conventional phenolic developer, It is considered that the image storability is improved. However, with some effect, the degree is still not enough.

[0007] Further, many examples of using a urea or thiourea compound as a color developing agent have been filed, such as Japanese Patent Application Laid-Open No. 58-21496, and a color developing agent more effective for image preservation has been filed. Urea and thiourea derivatives are being searched for development. For example, JP-A-59-
Phenylurea or phenylthiourea compounds described in JP-A-184694, thiourea dimer compounds described in JP-A-60-145883, halogen-introduced diphenylthiourea compounds described in JP-A-61-211085, And a benzylthiourea compound described in Japanese Patent No. 185739. However, when thermal recording paper is made using these materials, the effect of short-term plasticizer resistance and oil resistance test is effective, but the long-term test shows image disappearance, and the effect of improving image storability is insufficient. is there. Further, Japanese Unexamined Patent Publication No.
No. 147357 discloses an example using a sulfonylurea compound as a color developer. Although this shows excellent image storability, it has a problem of ground color development in a plasticizer resistance test and a drawback that water resistance is rather weak.

Further, there is an example in which a sulphonamide group is introduced into a urea or thiourea compound.
7 and JP-A-8-59603, JP-A-8-25810
And diphenylthiourea sulfonamide compounds described in JP-A-8-132939. Although they exhibit excellent image storability, they have the disadvantage of developing ground color in heat resistance tests.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat-sensitive recording material having improved image storability of a recording portion and heat-resistant ground color stability of a blank portion.

[0010]

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, a compound having two phenylsulfamoyl groups and two urea structures in one molecule was found to be a thermosensitive recording medium. Have been found to exhibit excellent functions as color developers, and have completed the present invention. Also,
Particularly, the compound represented by the following general formula (1) is effectively used in the present invention.

[0011]

Embedded image (However, R ¹ and R ² each represent an alkyl group, an alkoxy group, or an electron-withdrawing group. M represents an integer of 0 to 5. n
Represents an integer of 0 to 4. A represents a divalent group. )

In the compound of the present invention represented by the general formula (1), A represents a divalent group. Representative examples of the group belonging to A are shown in the following formulas (5) and (6), but the present invention is not limited to these.

[0013]

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[0014]

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Further, the following general formulas (2), (3),
The compound represented by (4) is a more useful compound.

[0016]

Embedded image (However, R ³ and R ⁴ each represent an alkyl group, an alkoxy group, or an electron-withdrawing group. O represents an integer of 0 to 5. p
Represents an integer of 0 to 4. )

[0017]

Embedded image (However, R ⁵ , R ⁶ , and R ⁷ each represent an alkyl group, an alkoxy group, or an electron-withdrawing group. Q represents an integer of 0 to 5. r and s represent an integer of 0 to 4.)

[0018]

Embedded image (However, R ⁸ and R ⁹ each represent an alkyl group, an alkoxy group, or an electron-withdrawing group. T represents an integer of 0 to 5; u
Represents an integer of 0 to 4. v represents an integer of 2 to 12. )

Here, R ^{1 to} R ⁹ may be any substituents which do not impair color development and image storability when the compound is used as a color developer. Among these, from the viewpoints of stability of color developing ability and color sensitivity, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom such as chlorine, bromine, fluorine, or a nitro group as an electron-withdrawing group. , An alkoxycarbonyl group,
Nitrile groups are preferred.

The compound of the present invention is a so-called non-phenol type developer having no hydroxy group in the molecule but having a color developing ability to form a dye precursor, and has a phenylsulfamoyl group and a urea structure in one molecule. Is a compound having two each. The thermosensitive recording medium produced using this, the plasticizer resistance and oil resistance of the recording part,
Image storability such as water resistance is greatly improved. The reason is not clear, but is presumed as follows.

In general, compounds having a urea structure are hardly soluble in oils, plasticizers and various solvents, and therefore do not elute even when exposed to them. There is a tendency for good image storability to be obtained without image loss. On the other hand, the present inventors have found that a phenylsulfamoyl group also contributes to image storability, and as a result of intensive studies, the compounds of the present invention have achieved good image storability and sufficient color developing ability. It has been found that the obtained developer is an excellent developer. It is considered that the effect is further increased by increasing the number of urea structures contained in one molecule, but there is a concern that the melting point or decomposition point of the compound may be sharply increased and the color developing ability may be reduced. On the other hand, the phenylsulfamoyl group is considered to act to lower the melting point of the urea compound to maintain the color developing ability, and the presence of two each provides a balance between image storability and color developing ability. It is presumed that good and excellent quality performance can be obtained.

Further, according to the present invention, not only the image storability is improved, but also the excellent heat-resistant ground color stability of the blank portion is obtained. This is considered to be one of the reasons that the present compound has a urea structure in the molecule. Usually, urea exists in a keto form (—NHC (＝ O) NH—), but when printing, very large heat energy is applied for a short time by a thermal head or the like. At that time, the enol type (-N = C
(-OH) NH-), and it is presumed that the color developing ability is exhibited here for the first time. On the other hand, the temperature at which the stability of the heat-resistant ground color is required is about 90 to 120 ° C. At this temperature, conversion to the enol type does not occur and the color developing ability is not exhibited. It is considered that the color does not deteriorate. In addition, it is presumed that one of the reasons is that the compound of the present invention has a higher melting point than conventional phenolic developers. The heat-sensitive recording medium contains, in addition to the color developer, an organic compound that is melted by heat, such as a dye precursor or a sensitizer. Therefore, the eutectic point of these mixtures is relatively low, and even when heated at about 100 ° C., there is a tendency that the color development reaction proceeds and the ground color deteriorates, but it is considered that a developer having a higher melting point is less likely to do so.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The compound of the present invention can be synthesized by the following method. First, an acetamidobenzenesulfonyl chloride compound and an aniline compound are reacted to synthesize an acetamido-N-phenylbenzenesulfonamide compound. Next, an acetyl group is eliminated by a hydrolysis reaction to lead to an amino-N-phenylbenzenesulfonamide compound. Furthermore, the amino-N-phenylbenzenesulfonamide compound is prepared by a conventionally known method (for example, New Experimental Chemistry Course 14 Synthesis and Reaction of Organic Compounds [III] P.16).
31) can be synthesized. Specifically, diisocyanate and amino-N-phenylbenzenesulfonamide dissolved in an inert solvent such as acetone or THF are mixed under an inert gas atmosphere, and the mixture is stirred at room temperature for several minutes to several hours to achieve the intended purpose. Can be synthesized.

As another method, a urea dimer is synthesized by reacting a diisocyanate compound with two molecules of an aniline compound. Next, the terminal phenyl group is reacted with chlorosulfuric acid to form disulfonyl chloride, and further reacted with two molecules of the aniline compound to obtain a target compound.

Diphenylmethane-4,4'-diisocyanate (trade name: MDI) as a raw material of the compound of the present invention
And tolylene-2,4-diisocyanate <2,4-TD
I>, tolylene-2,6-diisocyanate <2,6-
TDI>, 1,6-hexamethylene diisocyanate <
When HDI> or the like is used, it is very easily and inexpensively available because it is industrially produced in large quantities as a paint, an adhesive, or a polyurethane raw material. Also, the production can be performed at a high yield without requiring any special equipment. Therefore, there is an advantage that the production cost of the color developer of the present invention is very low.

The following compounds are illustrated as specific examples of the compound used in the present invention, but the present invention is not limited to these.

[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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In order to produce the thermosensitive recording medium of the present invention, various known production methods can be used. Specifically, it can be produced by the following method. That is,
The compound of the present invention, the dye precursor, and the sensitizer are each atomized by a pulverizer or an emulsifier such as a ball mill, an attritor, and a sand grinder, and various fillers and various additives are added, and dispersed in an aqueous solution of a water-soluble binder. Paint
When this is applied to an arbitrary support with various coaters such as an air knife coater, a blade coater and a roll coater, a heat-sensitive recording material is obtained. The compounds of the present invention may be used alone or in combination of two or more.

As the dye precursor used in the heat-sensitive recording medium of the present invention, conventionally known dye precursors can be used. The dye precursor is illustrated below, but the present invention is not limited thereto, and two or more of these may be used in combination.

3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide <trade name: CVL
>, 3-diethylamino-6-methyl-7-anilinofluoran <ODB>, 3-dibutylamino-6-methyl-7-anilinofluoran <ODB-2>, 3- (N-
Isoamyl-N-ethylamino) -6-methyl-7-anilinofluoran <S-205>, 3-diethylamino-7-m-trifluoromethylanilinofluoran <B
rack-100>, 3-dibutylamino-7-o-chloroanilinofluoran <TH-107>, 3- (N-
Cyclohexyl-N-methylamino) -6-methyl-7
-Anilinofluoran <PSD-150>, 3-diethylamino-7-anilinofluoran <Green-2
>, 3,3-bis (4-dimethylaminophenyl) phthalide <MGL>, tris [4- (dimethylamino) phenyl] methane <LCV>, 3,3-bis (1-ethyl-
2-methylindol-3-yl) phthalide <indolyl red>, 3-cyclohexylamino-6-chlorofluoran <OR-55>, 3,3-bis [2- (p-dimethylaminophenyl) -2- (P-methoxyphenyl) ethenyl] -4,5,6,7-tetrachlorophthalide <NIR-Black>, 1,1,5,5-tetrakis (p-dimethylaminophenyl) -3-methoxy-
1,4-pentadiene, 1,1,5,5-tetrakis (p-dimethylaminophenyl) -3- (p-dimethylaminophenyl) -1,4-pentadiene.

In the present invention, the compound of the present invention can be used in combination with one or more known developers which have been conventionally used. The following are examples of color developers, but the present invention is not limited to these.

4,4'-isopropylidene diphenol, 1,7-di (4-hydroxyphenylthio) -3,
Bisphenols such as 5-dioxaheptane and 4,4′-cyclohexylidenediphenol, benzyl 4-hydroxybenzoate, ethyl 4-hydroxybenzoate,
-4-hydroxybenzoic acid esters such as normal propyl hydroxybenzoate, isopropyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, dimethyl 4-hydroxyphthalate, diisopropyl 4-hydroxyphthalate, dibenzyl 4-hydroxyphthalate , 4-
4-hydroxyphthalic acid diesters such as dihexyl hydroxyphthalate, monobenzyl phthalate,
Monoesters of phthalic acid such as monocyclohexyl phthalate, monophenyl phthalate, and monomethylphenyl phthalate, bis (4-hydroxy-3-tert-butyl-6-methylphenyl) sulfide, bis (4-hydroxy- 2,5-dimethylphenyl) sulfide, bis (4-hydroxy-2-methyl-)
Bishydroxyphenyl sulfides such as 5-ethylphenyl) sulfide, 4-hydroxy-4′-isopropoxydiphenyl sulfone, 4-hydroxy-4′-
4-hydroxyphenylarylsulfones such as methyldiphenylsulfone, 4-hydroxy-4′-normalpropoxydiphenylsulfone, 4-hydroxyphenylbenzenesulfonate, 4-hydroxyphenyl-
p-tolylsulfonate, 4-hydroxyphenyl-p
4-hydroxyphenylarylsulfonates such as -chlorobenzenesulfonate; 1,3-di [2- (4
-Hydroxyphenyl) -2-propyl] benzene,
1,3-di [2- such as 1,3-di [2- (4-hydroxy-3-methylphenyl) -2-propyl] benzene
(Hydroxyphenyl) -2-propyl] benzenes,
Benzyl 4-hydroxybenzoyloxybenzoate, 4
Methyl-hydroxybenzoyloxybenzoate, ethyl 4-hydroxybenzoyloxybenzoate, normal propyl 4-hydroxybenzoyloxybenzoate, 4-
Isopropyl hydroxybenzoyloxybenzoate, 4
4 such as butyl hydroxybenzoyloxybenzoate;
-Hydroxybenzoyloxybenzoates, bis (3-tert-butyl-4-hydroxy-6-methylphenyl) sulfone, bis (3-ethyl-4-hydroxyphenyl) sulfone, bis (3-propyl-4-hydroxy) Phenyl) sulfone, bis (3-isopropyl-4-hydroxyphenyl) sulfone, bis (3-ethyl-4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfone, 2-hydroxyphenyl-4′-hydroxyphenylsulfone Bishydroxyphenylsulfones such as bis (3-chloro-4-hydroxyphenyl) sulfone, bis (3-bromo-4-hydroxyphenyl) sulfone, p-tert-butylphenol, p-phenylphenol, p-benzylphenol, 1-naft Phenols such as phenol, 2-naphthol, benzoic acid, p-tert-butylbenzoic acid, trichlorobenzoic acid, 3-sec-butyl-4-hydroxybenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid, 3, Metal salts of aromatic carboxylic acids such as 5-dimethyl-4-hydroxybenzoic acid, terephthalic acid, salicylic acid, 3-isopropylsalicylic acid, and 3-tert-butylsalicylic acid.

In a heat-sensitive recording medium containing a dye precursor and a color developer as a color-forming component, a sensitizer is usually used to enhance the color-forming sensitivity. Examples of the sensitizer are shown below, but the present invention is not limited to these, and two or more of these may be used in combination.

Stearic acid, stearic acid amide, palmitic acid amide, oleic acid amide, behenic acid, ethylenebisstearamide, coconut fatty acid amide, montan wax, polyethylene wax, phenyl-α-naphthyl carbonate, di-p-tolyl Carbonate, diphenyl carbonate, 4-biphenyl-p-tolyl ether, p-benzylbiphenyl, m-terphenyl, triphenylmethane, 1,1,3-tris (2-methyl-
4-hydroxy-5-tert-butylphenyl) butane, 1,2-bis (3-methylphenoxy) ethane,
1,2-bisphenoxyethane, 1,2-bis (4-methylphenoxy) ethane, 1,4-bisphenoxybutane, 1,4-bisphenoxybutene, 2-naphthylbenzyl ether, 1,4-di Ethoxynaphthalene, 1,4
-Dimethoxynaphthalene, 1-hydroxy-2-naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid methyl ester, 2-naphthoic acid phenyl ester,
benzyl p-benzyloxybenzoate, dibenzyl terephthalate, dimethyl terephthalate, 1,1-diphenylethanol, 1,1-diphenyl-2-propanol,
1,3-diphenoxy-2-propanol, p- (benzyloxy) benzyl alcohol, normal octadecylcarbamoyl-p-methoxycarbonylbenzene, normal octadecylcarbamoylbenzene.

In the present invention, various auxiliaries may be added in order to improve the stability of the recorded image. The auxiliaries are exemplified below, but the present invention is not limited to these.

Zinc stearate, aluminum stearate, calcium stearate, zinc palmitate, zinc behenate, metal salts of p-chlorobenzoate (Zn, C
a), p-nitrobenzoic acid metal salt (Zn, Ca), phthalic acid monobenzyl ester metal salt (Zn, Ca), 4,
4'-isopropylidene-bis (3-methyl-6-te
rt-butyl) phenol.

As the binder used in the heat-sensitive recording medium of the present invention, those conventionally known in the field of heat-sensitive recording can be used. Examples of the binder are shown below, but the present invention is not limited thereto.

Completely saponified polyvinyl alcohol having a degree of polymerization of 2000 or less, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, other modified polyvinyl alcohol, hydroxy Ethyl cellulose, methyl cellulose,
Cellulose derivatives such as carboxymethylcellulose and acetylcellulose, casein, gelatin, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, polymers and copolymers such as styrene, vinyl acetate, acrylamide and acrylate, polyamide Resins, silicone resins, petroleum resins, terpene resins, ketone resins, coumarone resins, and others can be mentioned. These natural and synthetic polymer substances can be used by dissolving them in water or an organic solvent such as alcohol, or can be used in a state of being emulsified or dispersed in a paste form in a medium such as water. Also, two or more of these can be used.

The filler used in the thermosensitive recording medium of the present invention includes clay, calcined clay, diatomaceous earth, talc, kaolin, calcium carbonate, basic magnesium carbonate, barium sulfate, barium carbonate, aluminum hydroxide, zinc oxide, silica , Magnesium hydroxide, titanium oxide, urea
Formalin resin, polystyrene resin, phenol resin,
Other natural or synthetic inorganic or organic fillers may be mentioned, but are not limited thereto. Two or more of these can be used.

As additives, ultraviolet absorbers, defoamers,
Examples include a fluorescent whitening agent, a waterproofing agent, a lubricant and the like, but the present invention is not limited to these.

The amounts of the dye precursor and the developer used in the thermosensitive recording medium of the present invention and the types and amounts of other various components are determined according to the required performance and recording suitability, and are not particularly limited. Usually, with respect to 1 part of the dye precursor,
The developer is preferably 1 to 8 parts and the filler is preferably 1 to 20 parts, and the binder is preferably 10 to 25% of the total solid content.

As the support used in the heat-sensitive recording medium of the present invention, paper such as high-quality paper, medium-quality paper, coated paper, synthetic paper,
Although a plastic film etc. can be mentioned, this invention is not limited to these.

For the purpose of further improving the storage stability, an overcoat layer of a polymer substance or the like can be provided on the thermosensitive coloring layer. Further, for the purpose of enhancing the storage stability and sensitivity, an undercoat layer containing an organic filler or an inorganic filler may be provided between the color-forming layer and the support.

[0050]

The following examples illustrate the synthesis examples of the compounds of the present invention, the synthesis examples of starting materials suitable for the production thereof, and the production examples of thermosensitive recording materials using them as color developers. This will be specifically described. In addition, the reactants and other components used are shown as representative examples, and various modifications can be made as described above within the scope of the present invention.

-Synthesis of Compound of the Present Invention- [Synthesis Example of Starting Material] Synthesis of 4-amino-N-phenylbenzenesulfonamide 4-acetamidobenzenesulfonyl chloride
0 g of methyl ethyl ketone 250 ml, water 300 ml,
18.6 g of sodium carbonate was added and dissolved. 13.6 g of aniline was added thereto and reacted at room temperature for 1 hour. After that, 4N-sodium hydroxide aqueous solution 170ml
Was added and heated under reflux for 16 hours to cause a reaction. The solvent was distilled off using an evaporator, and the residue was acidified by adding 6N-hydrochloric acid, and the resulting solid was collected by filtration. This was recrystallized from ethyl acetate to obtain 29.4 g (yield 81%) of 4-amino-N-phenylbenzenesulfonamide as a white solid. <IR spectrum> (KBr tablet method, cm ^-1 ) 3420,3349,3294,3246,1638,1596,1495,1465,1435,1394,
1319,1301,1220,1152,1093,1072,918,891,831,751,691,
561 ^<1 H-NMR _{spectrum> (300MHz, DMSO-d 6} , δ / ppm, TMS) 5.92 (2H, s, NH 2), 6.52 (2H, d, J = 9Hz, ArH), 6.96 (1H, t , J = 7H
z, ArH), 7.06 (2H, d, J = 8Hz, ArH), 7.18 (2H, t, J = 8Hz, ArH),
7.38 (2H, d, J = 8Hz, ArH), 9.82 (1H, s, NH) <13 C-NMR _{spectrum> (75MHz, DMSO-d 6} , δ / ppm, TMS) 112.50,119.36,123.18,124.43, 128.62,128.83,138.44,1
52.73 <MS spectrum> (FAB-MS (M / Z)) 249 (M + H) ⁺

Synthesis Example 1 Synthesis of 4,4'-bis (4-phenylsulfamoylphenylureido) diphenylmethane (A-01) 4-amino-N-phenylbenzenesulfonamide
37 g was dissolved in 30 ml of THF. Under a nitrogen atmosphere, a solution prepared by dissolving 2.0 g of MDI in 20 ml of THF was added dropwise, and the mixture was reacted by heating under reflux for 6 hours. After completion of the reaction, the solvent was distilled off using an evaporator, and the residue was recrystallized from ethyl acetate to give 4,4′-bis (4-phenylsulfamoylphenylureido) diphenylmethane (A-0).
4.54 g (yield 76%) of 1) white solid was obtained. <Decomposition point> 260-270 ° C <IR spectrum> (KBr tablet method, cm ^-1 ) 3372,3190,1702,1594,1536,1512,1408,1313,1232,1152,
1094,923,825,754,696,597,553 ^<1 H-NMR _{spectrum> (300MHz, DMSO-d 6} , δ / ppm, TMS) 3.82 (2H, s, CH 2), 6.98 (2H, t, J = 7Hz, ArH), 7.10 (8H , d, J = 7H
z, ArH), 7.19 (4H, t, J = 8Hz, ArH), 7.34 (4H, d, J = 8Hz, ArH),
7.55 (4H, d, J = 9Hz, ArH), 7.64 (4H, d, J = 9Hz, ArH), 8.68 (2H,
s, NH), 9.00 (2H , s, NH), 10.07 (2H, s, SO 2 NH) <13 C-NMR _{spectrum> (75MHz, DMSO-d 6} , δ / ppm, TMS) 59.59,117.26,118.51 , 119.77,123.56,127.85,128.80,13
1.57,135.22,136.99,137.91,143.74,151.99,181.02 <MS spectrum> (FAB-MS (M / Z)) 747 (M + H) ⁺

[Synthesis Example 2] 2,4-bis (4-phenylsulfamoylphenylureido) toluene (A-1)
4. Synthesis of 3) 4-amino-N-phenylbenzenesulfonamide
50 g was dissolved in 30 ml of THF. Under a nitrogen atmosphere, a solution in which 1.75 g of 2,4-TDI was dissolved in 20 ml of THF was added dropwise, and the mixture was reacted by heating under reflux for 6 hours.
After the completion of the reaction, the solvent was distilled off using an evaporator, and the residue was recrystallized from ethyl acetate to give 2,4-bis (4-phenylsulfamoylphenylureido) toluene (A-13)
2.82 g (42% yield) of a white solid was obtained. <Melting point> 218-220 ° C <IR spectrum> (KBr tablet method, cm ^-1 ) 3352,1695,1596,1537,1499,1450,1410,1313,1220,1153,
1094,923,828,753,697,616,595,556 ^<1 H-NMR _{spectrum> (300MHz, DMSO-d 6} , δ / ppm, TMS) 2.24 (3H, s, CH 3), 6.94-7.24 (13H, m, ArH), 7.53-7.67 (8H ,
m, ArH), 8.45 (1H, s, NH), 8.81 (1H, s, NH), 9.01 (1H, s, NH),
9.46 (1H, s, NH) <13 C-NMR _{spectrum> (75MHz, DMSO-d 6} , δ / ppm, TMS) 17.12,110.94.112.34.116.88.119.28,119.79.123.16.12
7.69.128.56,129.91,131.62,137.35,138.18,143.57,15
1.91,180.90 <MS spectrum> (FAB-MS (M / Z)) 671 (M + H) ⁺

Synthesis Example 3 1,6-bis (4-phenylsulfamoylphenylureido) hexane (A-2
3. Synthesis of 5) 4-amino-N-phenylbenzenesulfonamide
87 g was dissolved in 30 ml of THF. Under a nitrogen atmosphere, a solution in which 1.50 g of HDI was dissolved in 20 ml of THF was added dropwise, and the mixture was reacted by heating under reflux for 6 hours. After the completion of the reaction, the solvent was distilled off using an evaporator, and the residue was recrystallized from ethyl acetate to obtain 3.67 g of a white solid of 1,6-bis (4-phenylsulfamoylphenylureido) hexane (A-25). (62% yield). <Melting point> 237-239 ° C <IR spectrum> (KBr tablet method, cm ^-1 ) 3382,3343,3140,2930,2860,2272,1685,1594,1543,1497,
1405,1321,1242,1151,1095,925,833,755,701,593,552 ^<1 H-NMR _{spectrum> (300MHz, DMSO-d 6} , δ / ppm, TMS) 1.29-1.42 (8H, m, CH 2), 3.07 (4H, q, J = 6Hz, NCH ₂ ), 6.25 (2H,
t, J = 5Hz, CONH), 6.98 (2H, t, J = 7Hz, ArH), 7.08 (4H, d, J = 8H
z, ArH), 7.19 (4H, t, J = 8Hz, ArH), 7.48 (4H, d, J = 9Hz, ArH),
7.58 (4H, d, J = 9Hz, ArH), 8.80 (2H, s, ArNHCO), 10.03 (2H, s,
NHSO ₂ ) < ¹³ C-NMR spectrum> (75 MHz, DMSO-d ₆ , δ / ppm, TMS) 26.01, 29.51, 97.44, 116.66, 119.07, 123.53, 127.81, 128.
83,130.65,137.94,144.54,154.53,180.94 <MS spectrum> (FAB-MS (M / Z)) 671 (M + H) ⁺

-Synthesis of Compound of Comparative Example- [Synthesis Example 4] 4,4'-diphenylsulfamoyl-
Synthesis of N, N'-diphenylurea (B-03) While cooling 25 ml of chlorosulfuric acid in an ice-water bath,
10 g of N, N'-diphenylurea was gradually added.
Thereafter, the mixture was reacted by stirring at room temperature for 4 hours. The reaction solution was poured into ice to obtain 4,4′-dichlorosulfonyl-N, N′-diphenylurea as a white solid. Acetone (100 ml) and pyridine (100 ml) were added to and dissolved therein, and aniline (8.77 g) was added dropwise while immersing in an ice water bath and cooling.
Thereafter, the mixture was reacted by stirring at 30 ° C. for 2 hours. Acetone in the reaction solution was distilled off using an evaporator, and the residue was acidified by adding diluted hydrochloric acid. The residue was extracted with ethyl acetate and the solvent was distilled off. The residue was recrystallized from acetone + ethyl acetate to give 4,4 '.
5.41 g of a white solid of -diphenylsulfamoyl-N, N'-diphenylurea (B-03) (yield 22
%)Obtained. <Decomposition point> 283 ° C <IR spectrum> (KBr tablet method, cm ^-1 ) 3376,3305,3268,3189,1716,1594,1553,1541,1495,1407,
1342,1322,1243,1215,1149,1095,933,913,900,830,757,
697,664,563,543 < ¹ H-NMR spectrum> (300 MHz, DMSO-d ₆ , δ / ppm, TMS) 7.00 (2H, t, J = 7 Hz, ArH), 7.10 (4H, d, J = 8 Hz, ArH), 7.22 ( 4H,
t, J = 7Hz, ArH), 7.58 (4H, t, J = 9Hz, ArH), 7.71 (4H, d, J = 9Hz,
ArH), 9.23 (2H, s , NHCONH), 10.16 (1H, s, NHSO 2) <13 C-NMR _{spectrum> (75MHz, DMSO-d 6} , δ / ppm, TMS) 117.9,119.9,123.8,128.0, 129.1,132.2,137.9,143.3,15
1.8 <MS spectrum> (FAB-MS (M / Z)) 523 (M + H) ⁺

-Production of thermosensitive recording medium- [Examples 1 to 3] Thermosensitive recording media comprising the following compositions were produced. That is, first, a dye dispersion (solution A) and a developer dispersion (solution B) having the following composition were each ground by a sand grinder to an average particle diameter of 1 μm. (Solution A: dye dispersion) 3-N, N-diethylamino-6-methyl-7-anilinofluoran 2.0 parts 10% aqueous polyvinyl alcohol solution 4.6 parts Water 2.6 parts (Solution B: color development Agent Dispersion) Compound of the present invention (see Tables 1 and 2) 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts water 11.2 parts Then, dispersion liquid of liquid A, liquid B and kaolin clay at the following ratios Was mixed to obtain a heat-sensitive paint. Solution A: Dye dispersion 9.2 parts Solution B: developer dispersion 36.0 parts Kaolin clay (50% dispersion) 12.0 parts Amount of this heat-sensitive paint applied to one side of a 50 g / m ² base paper 6.
The sheet was coated and dried so as to have a thickness of 0 to 6.5 g / m ² , and this sheet was treated with a super calender so that the smoothness became 500 to 600 seconds, thereby producing a thermosensitive recording medium.

[Comparative Examples 1 to 3] In the same manner as in Examples 1 to 3, except that the following developer was used in place of the compound of the present invention in the developer dispersion (solution B). A recording medium was produced. 4-hydroxy-4'-isopropoxydiphenylsulfone (B-01) N, N'-diphenylurea (B-02) 4,4'-diphenylsulfamoyl-N, N'-diphenylurea (B-03)

-Evaluation of thermal recording medium- [Coloring method]
01 (made by UBI) with an applied energy of 450 m
At j / mm ² , recording was performed on the produced thermosensitive recording medium. Next, the image density of the recording portion and the blank portion was measured by a Macbeth densitometer (RD-914, using an amber filter). Using this as a test sample, the following test was performed. [Plasticizer resistance test]: The test sample was brought into contact with a vinyl chloride film (Dialup 300G, manufactured by Mitsubishi Plastics, Inc.), left at 40 ° C. for 24 hours, and the image remaining density of the recording portion was measured with a Macbeth densitometer. . [Oil resistance test]: The test sample was immersed in salad oil for 1 hour, the oil was wiped off, left at room temperature for 24 hours, and the residual image density of the recording portion was measured with a Macbeth densitometer. [Water resistance test]: The test sample was immersed in tap water for 24 hours, dried at 30 ° C. for 2 hours, and the image remaining density of the recording portion was measured with a Macbeth densitometer. [Heat-resistant ground color test of blank portion]: The test sample was left at 100 ° C. for 30 minutes, and the density of the blank portion was measured with a Macbeth densitometer. Table 1 shows the results of the image storability test of the image recording portion, and Table 2 shows the results of the heat-resistant ground color test of the blank portion. In Table 1, the larger the value, the better the image storability, and in Table 2, the smaller the value, the better the stability of the heat-resistant ground color.

[0059]

[Table 1] Image storage test results

[Table 2] Table 2. Results of heat resistant ground color test

As is evident from the results of Tables 1 and 2, Examples 1 to 3 using the compound of the present invention as a developer were Comparative Examples 1 and phenylsulfur using a conventional phenolic developer. Compared to Comparative Example 2 of a urea-based developer having no moyl group, and Comparative Example 3 of a urea-based developer having two phenylsulfamoyl groups but having only one urea structure, the oil resistance is higher. Not only are the properties and plasticizer resistance significantly improved, but also the water resistance is good, and the heat resistant ground color stability of the white paper portion is also excellent.

[0061]

The compounds of the present invention have sufficient ability to form a dye precursor. Further, a heat-sensitive recording material using this compound as a color developer is extremely useful because it is very excellent in image storability of a recording portion and heat-resistant ground color stability of a blank portion.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Seiki Yoneshige 5-2-1-1, Oji, Kita-ku, Tokyo Nippon Paper Industries Central Research Laboratory (72) Inventor Hidetoshi Yoshioka 5-2-1-1, Oji, Kita-ku, Tokyo No. Nippon Paper Industries Central Research Laboratory

Claims (5)

[Claims] 1. A thermosensitive recording medium having a thermosensitive coloring layer containing a colorless or pale-colored dye precursor and a developer which reacts upon heating to form the dye precursor, wherein phenylsulfur is used as the developer. A thermosensitive recording material, which is a compound having two moyl groups (PhNHSO ₂ —) and _two urea structures in one molecule. 2. The thermosensitive recording medium according to claim 1, wherein the developer is a compound represented by the following general formula (1). Embedded image (However, R ¹ and R ² each represent an alkyl group, an alkoxy group, or an electron-withdrawing group. M represents an integer of 0 to 5. n
Represents an integer of 0 to 4. A represents a divalent group. ) 3. The thermosensitive recording medium according to claim 2, wherein the developer is a compound represented by the following general formula (2). Embedded image (However, R ³ and R ⁴ each represent an alkyl group, an alkoxy group, or an electron-withdrawing group. O represents an integer of 0 to 5. p
Represents an integer of 0 to 4. ) 4. The heat-sensitive recording material according to claim 2, wherein the developer is a compound represented by the following general formula (3). Embedded image (However, R ⁵ , R ⁶ , and R ⁷ each represent an alkyl group, an alkoxy group, or an electron-withdrawing group. Q represents an integer of 0 to 5. r and s represent an integer of 0 to 4.) 5. The thermosensitive recording medium according to claim 2, wherein the color developer is a compound represented by the following general formula (4). Embedded image (However, R ⁸ and R ⁹ each represent an alkyl group, an alkoxy group, or an electron-withdrawing group. T represents an integer of 0 to 5; u
Represents an integer of 0 to 4. v represents an integer of 2 to 12. )